1. Field of the Invention
The present invention relates to a display screen turning apparatus, and more particularly, it relates to a display screen turning apparatus comprising a display screen support member provided on the side of a display screen and a base support member provided on the side of a base.
2. Description of the Background Art
A display screen turning apparatus or the like for vertically or horizontally turning a display screen by a prescribed angle is known in general, as disclosed in each of Japanese Utility Model Registration Nos. 3079007 and 3092391, Japanese Patent Laying-Open No. 2001-146874, National Patent Publication Gazette No. 2004-522918 and Japanese Patent Laying-Open No. 2006-64786, for example.
The aforementioned Japanese Utility Model Registration No. 3079007 discloses a monitor positioner (display screen turning apparatus) comprising a fixed seat fixed onto a main seat (base) and provided with a figure-eight limiting hole on a surface arranged vertically from the main seat, a pivot (shaft) provided with a through-shaft axially extending from a first side surface of a pivot main body (round shaft) and having outer peripheral surfaces partially formed by planar portions parallel to each other and a fixed plate provided on a second side surface of the pivot main body (round shaft) for fixing a monitor, an oil-impregnated washer, an elastic plate and a nut. In this monitor positioner (display screen turning apparatus) described in Japanese Utility Model Registration No. 3079007, the through-shaft of the pivot is inserted into the figure-eight limiting hole of the fixed seat and clamped by the nut through the oil-impregnated washer and the elastic plate, to be rotatably supported in the figure-eight limiting hole. When the monitor is rotated frontward or rearward by a prescribed angle from a state perpendicularly arranged with respect to the main seat in this monitor positioner, the planar portions of the through-shaft of the pivot come into contact with the inner side surface of the figure-eight limiting hole, thereby regulating the rotational range of the monitor.
The aforementioned Japanese Utility Model Registration No. 3092391 discloses a video camera pan head comprising a pair of side plates, including arcuate slits having central points coinciding with the rotation center of a video camera, provided on both side surfaces of a root portion (base) and a vertical moving portion, held between the pair of side plates, having an arbor (shaft) movably fitted into the arcuate slits of the side plates. In this video camera pan head described in Japanese Utility Model Registration No. 3092391, gears are so rotationally driven as to move the arbor of the vertical moving portion along the slits of the side plates, thereby vertically swinging the video camera placed on the vertical moving portion. When the video camera is rotated upward or downward by a prescribed angle from a state horizontally placed on this video camera pan head, the arbor comes into contact with the terminals of the slits, thereby regulating the swinging range of the vertical moving portion.
The aforementioned Japanese Patent Laying-Open No. 2001-146874 discloses an OA apparatus tilting structure (display screen turning apparatus) comprising a fixing bracket fixed to a stand arranged vertically from a horizontal plane and provided with a rotation center hole and an arcuate slot concentric with the rotation center hole, a rotation-side bracket, fixed to the rear surface of a liquid crystal monitor, provided with a shaft and a subshaft on a position opposite to the fixing bracket, a plurality of spring washers and nuts. In this OA apparatus tilting structure (display screen turning apparatus) described in Japanese Patent Laying-Open No. 2001-146874, the shaft and the subshaft are inserted into the rotation center hole and the arcuate slot of the fixing bracket respectively and clamped by the nuts through the plurality of spring washers, so that the subshaft of the rotation-side bracket is movably supported in the slot. When the monitor is rotated upward by a prescribed angle from a state vertically arranged on the OA apparatus tilting structure, the subshaft of the rotation-side bracket reaches the terminal of the arcuate slot, thereby regulating the rotational range of the monitor.
The aforementioned National Patent Publication Gazette No. 2004-522918 discloses a flat liquid crystal display support (display screen turning apparatus) comprising a hollow shaft arm horizontally supported on a pole (support post) arranged vertically from a horizontal plane by a stirrup (clamp member), a cage (holding member) fixed to the forward end of the arm and provided with a semispherical inner surface, a ball fixed to the rear surface of a flat liquid crystal screen and provided with a semispherically formed surface, a tie rod (coupling rod) and an adjusting nut. In this flat liquid crystal display support (display screen turning apparatus) described in National Patent Publication Gazette No. 2004-522918, the semicircular surface of the ball is slidably fitted with the inner surface of the cage while the tie rod passing through the cage and the ball from the inner part of the arm is clamped by the adjusting nut, thereby rotatably supporting the ball in the cage. When the flat liquid crystal screen is rotated upward, downward, leftward or rearward from a state vertically arranged on the flat liquid crystal display support, an annular end of the cage comes into contact with an end of the semicircular surface of the ball, thereby regulating the turning range of the flat liquid crystal screen.
The aforementioned Japanese Patent Laying-Open No. 2006-64786 discloses a liquid crystal display comprising a support member fixed to a base and an arm fixed to a liquid crystal panel and arranged in a vertical direction. In this liquid crystal display described in Japanese Patent Laying-Open No. 2006-64786, the lower end of the arm so is rotatably mounted on the support member as to rotate the liquid panel upward or downward by a prescribed angle from a vertically arranged state.
In the conventional monitor positioner proposed in the aforementioned Japanese Utility Model Registration No. 3079007, however, the planar portions of the through-shaft of the pivot come into contact with the inner side surface of the figure-eight limiting hole thereby regulating rotation of the monitor when the monitor is rotated frontward or rearward by the prescribed angle, while rotation of the through-shaft is not regulated when the monitor is vertically arranged with respect to the main seat. Therefore, the monitor (display screen) disadvantageously unnecessarily jolts due to insufficient clamping force (tightening torque of the nut) for the through-shaft with respect to the fixed seat or the own weight of the monitor. Further, the monitor positioner described in the aforementioned Japanese Utility Model Registration No. 3079007 is so formed as to rotate the through-shaft of the pivot along with the monitor. When turning means utilizing the driving force of an electric motor and a plurality of gear trains is applied to this monitor positioner, therefore, it is conceivably necessary to ensure a larger radius of rotation of the pivot meshing with the final gear of the gear trains thereby reducing influence exerted by a clearance between the gear trains (unnecessary rotation between gears) on the rotation angle of the pivot as a countermeasure for reducing the quantity of jolting upon rotation of the monitor resulting from the clearance (backlash) between the plurality of gear trains. If the radius of rotation of the pivot is merely increased, however, the size (height, for example) of the monitor positioner (display screen turning apparatus) may be disadvantageously increased.
In the conventional video camera pan head proposed in the aforementioned Japanese Utility Model Registration No. 3092391, the arbor of the vertical moving portion comes into contact with the terminals of the slits of the side plates thereby regulating rotation of the video camera when the video camera is rotated frontward or rearward by the prescribed angle from a horizontal position, while rotation of the arbor of the vertical moving portion is not regulated when the video camera stands still on a substantially horizontal position. Therefore, the vide camera disadvantageously unnecessarily jolts with the vertical moving portion due to a clearance (backlash) between the gears or the own weight of the video camera.
In the conventional OA apparatus tilting structure proposed in the aforementioned Japanese Patent Laying-Open No. 2001-146874, the subshaft of the rotation-side bracket comes into contact with the inner side surface of the slot thereby regulating rotation of the liquid crystal monitor when the liquid crystal monitor is rotated frontward or rearward by a prescribed angle, while rotation of the subshaft is not regulated when the liquid crystal monitor is vertically arranged. Therefore, the liquid crystal monitor (display screen) disadvantageously unnecessarily jolts due to insufficient tightening torque for the subshaft with respect to the fixing bracket or the own weight of the liquid crystal monitor. Further, the OA apparatus tilting structure described in the aforementioned Japanese Patent Laying-Open No. 2001-146874 is so formed as to rotate the shaft of the rotation-side bracket along with the liquid crystal monitor. When turning means utilizing the driving force of an electric motor and a plurality of gear trains is applied to this OA apparatus tilting structure, therefore, it is conceivably necessary to ensure a larger radius of rotation of the shaft meshing with the final gear of the gear trains thereby reducing influence exerted by a clearance between the gear trains (unnecessary rotation between gears) on the rotation angle of the shaft as a countermeasure for reducing the quantity of jolting upon rotation of the liquid crystal monitor resulting from the clearance (backlash) between the plurality of gear trains. If the radius of rotation of the shaft is merely increased, however, the size (height, for example) of the OA apparatus tilting apparatus (display screen turning apparatus) may be disadvantageously increased.
In the conventional flat liquid crystal display support proposed in the aforementioned National Patent Publication Gazette No. 2004-522918, the annular end of the cage comes into contact with the end of the ball thereby regulating rotation of the flat liquid crystal screen when the flat liquid crystal screen is rotated upward, downward, leftward or rearward by a prescribed angle, while rotation of the ball is not restricted when the flat liquid crystal screen is vertically set. Therefore, the flat liquid crystal screen disadvantageously unnecessarily jolts due to insufficient tightening torque of the adjusting nut with respect to the tie rod or the own weight of the flat liquid crystal screen.
The aforementioned Japanese Patent Laying-Open No. 2006-64786 proposing the conventional liquid crystal display neither discloses nor suggests a mechanism for rotating the arm with respect to the support member when the liquid crystal panel is anteroposteriorly rotated by a prescribed angle. Therefore, the liquid crystal panel (display screen) may disadvantageously unnecessarily jolt due to insufficient supporting in a support mechanism for rotatably supporting the arm with respect to the support member or the own weight of the liquid crystal panel.